TIG torch electrode

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jcfx
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TIG torch electrode

Post by jcfx » Mon Dec 16, 2019 4:58 pm

I just got started teaching myself TIG welding aluminum with a Lincoln SQ wave 200
and I have some questions about the electrode in the torch.

After using the torch for a while the electrode has hard dark gray deposit on it which makes getting the arc started
difficult I have to either brush it off or worse case regrind the tip.
Is this a normal occurrence or ares my settings are off ?

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warmstrong1955
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Re: TIG torch electrode

Post by warmstrong1955 » Mon Dec 16, 2019 5:29 pm

Not familiar with your Lincoln.....
I will assume you are using argon, at 15-20 cfh.
If there is a switch for the gas in your foot pedal, don't back off and stop the gas so quickly at the end of a weld.
If it has an automatic post flow for the gas, rather than a switch, you may need to increase the time.
Your symptoms sound like a lack of shielding gas, or not enough shielding gas, and often it's post flow.

Could be dirty or oily material. Contamination of the metal, will end up on the tungsten.
Clean.
Clean. Clean-clean-clean. Repairing old parts can be a chore sometimes. (Ask me about repairing cracked Cummins 855 oil pans.....things that make you go *&$%&)
I have dedicated stainless brushes I use for aluminum work only.

Bill
Today's solutions are tomorrow's problems.

jcfx
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Re: TIG torch electrode

Post by jcfx » Mon Dec 16, 2019 8:25 pm

Bill,
My setup is using 100% argon, 15 cfh, the pre flow and post flow about 15 sec is controlled by the
welding unit which unfortunately isn't user adjustable.
It could be that I had some contamination on the aluminum scraps I'm practicing on, I scrubbed them
with dedicated SS wire brush but did not solvent wipe them, I'll have to try again after I order some
more filler rods, I burned thru the two I bummed off a friend.

Another question I have is there a correlation to electrode size to filler rod size or is it all dependent on amps ?
My torch has a 3/32 electrode installed and I noticed when I switched to steel after running out of the aluminum filler rod
that the 1/8" E70 rods were having a difficult time melting.

Jim

LIALLEGHENY
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Re: TIG torch electrode

Post by LIALLEGHENY » Mon Dec 16, 2019 11:42 pm

You say that you have to regrind the tip when welding aluminum....are you balling the tungsten before you weld the aluminum? Are you welding the aluminum using AC with high frequency on? when you switch over to the steel are you also switching to DC-, high freq on start only? Your electrode size is dependent on the current being used, not the filler size. Current is dictated by the material and thickness being welded.

Nyle

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NP317
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Re: TIG torch electrode

Post by NP317 » Tue Dec 17, 2019 1:26 am

LIALLEGHENY wrote:
Mon Dec 16, 2019 11:42 pm
You say that you have to regrind the tip when welding aluminum....are you balling the tungsten before you weld the aluminum? Are you welding the aluminum using AC with high frequency on? when you switch over to the steel are you also switching to DC-, high freq on start only? Your electrode size is dependent on the current being used, not the filler size. Current is dictated by the material and thickness being welded.

Nyle
From another source:
"What is the best tungsten for TIG welding aluminum?
In selecting rare earth tungsten for TIG welding, the recommended options are 2 percent ceriated, 2 percent lanthanated or 1.5 percent lanthanated. Ceriated and lanthanated tungstens hold up better for AC TIG applications than 2 percent thoriated tungsten."

RussN

jcfx
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Re: TIG torch electrode

Post by jcfx » Tue Dec 17, 2019 2:08 am

Nyle - The lincoln manual said that the electrode tip was to be tapered but blunt, but I tried it both ways, as per the manual
and hand grinding a rounded tip, I got acceptable arc starts and got to laying down some dimes with a little fiddling of the
settings. Being new to all things tig I did dip the electrode into the puddle and had the melted the tip of the electrode a few times
till I got my footing. Hence the regrind.

My Lincoln Square Wave 200 does both AC/DC and when I switched to steel it was DC, aluminum was AC.
The reason I asked about electrode size was that the 1/8" steel filler rod had a hard time melting and joining the puddle I was forming,
it just balled up and rolled away from the puddle. So I assumed that the electrode size had something to do with it, but I was wrong.
This was at the end of my exploration of aluminum tigging, so when I switched to DC the steel which was not
prepped properly probably had a lot to do with with what I was experiencing.

Jim

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Re: TIG torch electrode

Post by LIALLEGHENY » Tue Dec 17, 2019 4:09 am

Proper way to weld aluminum on AC is to ball the tungsten. You will get a more stable arc that will hold up better at higher current. Grinding a blunt /rounded end is a lazy way to do it, and I have done it many times myself when feeling lazy. If your tungsten start to get fuzzy little hairs on the end, or melts off your exceeding the current the tungsten can handle for it's size. The balling helps prevent the fuzzy hairs as well, and choosing a different type of tungsten also helps, as stated above. Remember that aluminum wicks heat away from the work zone, thus requiring more current for the same thickness material as compared to steel, stainless etc. Because you are welding in AC your heat on time is also less than that of DC requiring more current. I don't know on your machine if you can adjust the AC balance or not. There are lots of variables that will effect what and how you are welding, one being the type and size of the cup you are using. Larger cup size for larger tungsten, and diffuser cups that I feel are better for aluminum, and also allow you to extend the tungsten out further, good for getting into corners.
Above all it's practice, practice, practice.

Nyle

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warmstrong1955
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Re: TIG torch electrode

Post by warmstrong1955 » Tue Dec 17, 2019 8:42 am

Sounds to me like you have dirty or oily material.
I use a SS brush, and acetone. Oxidation is also bad as well, and can penetrate more than just the surface. Anything permeated below the surface, will rise up when you weld it.
You may try a little for flow of argon too.

If you dip the filler rod, and it rolls away, you don't have a hot, or large enough puddle. Aluminum is tricky. It's harder to tell when the puddle is ready for a dab than steels. That's where Nyle's 'practice-practice-practice comes in. When the puddle is ready for a dab with the filler wire, it will sink, so watch for that.

I weld a lot of stainless steels, and use thoriated tungsten. (red) I don't use it on aluminum. I use lanthanated. (blue)
Thoriated won't ball.
Today's solutions are tomorrow's problems.

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GlennW
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Re: TIG torch electrode

Post by GlennW » Tue Dec 17, 2019 11:12 am

warmstrong1955 wrote:
Tue Dec 17, 2019 8:42 am
If you dip the filler rod, and it rolls away, you don't have a hot, or large enough puddle. Aluminum is tricky. It's harder to tell when the puddle is ready for a dab than steels. That's where Nyle's 'practice-practice-practice comes in.
You may also need to hold the torch more vertical. The angle of the torch can influence the direction of the heat. Imagine an acetylene torch. If it is aimed at the filler rod, it will melt the rod first...

Dipping too slowly can have that effect as well.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

LIALLEGHENY
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Re: TIG torch electrode

Post by LIALLEGHENY » Tue Dec 17, 2019 4:47 pm

"Thoriated won't ball" I use thoriated all of the time on aluminum and have no problem at all balling it. It doesn't hold the ball as well as other types of tungsten but does work quite well. Granted I have zirconiated on the shelf which is great for aluminum, but sometimes I get lazy....it's not like I am doing any x-ray welding where it really matters.

This is a great resource that gives you a better grasp of what is going on :https://www.millerwelds.com/resources/a ... er-welding

Nyle

Fastadam
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Re: TIG torch electrode

Post by Fastadam » Thu Jan 23, 2020 9:34 am

1/8" steel rod is huge. Material thickness and amperage will help dictate how much thickness you can push into the puddle. For most mild steels while using a 3/32 electrode I would recommend ER70S-2 welding rod with a diameter of either .045 or 1/16". If the filet you make is not big enough, you can always make multiple passes.

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